Projection exposure system

Abstract

A projection exposure system is proposed which is positionable between a first object and a second object for imaging the first object in a region of the second object with light of a wavelength band having a width deltalambda about a central working wavelength lambda, wherein a relative width deltalambda/lambda of the wavelength band is larger than 0.002, in particular, larger than 0.005, for example, of the Hg-I-line. The projection exposure system is a so-called three-bulge system comprising three bulges having, as a whole, a positive refractive power and two waists having, as a whole, a negative refractive power. By applying suitable measures, in particular, by suitably selecting the material for the lenses forming the projection exposure system, the long-term stability of the system is increased.

What is claimed is:  
     
       1. A projection exposure system positionable between a first object and a second object for imaging the first object in a region of the second object with light of a wavelength band having a width δλabout a central working wavelength λ, wherein a relative width δλ/λof the wavelength band is larger than 0.002, comprising: 
       at least a first, second, third, fourth and fifth lens group which are successively positioned in this order between the first and the second object along an optical axis and each of which comprises a plurality of lenses, wherein the first, third and fifth lens group each has a positive refractive power and the second and fourth lens group each has a negative refractive power, and wherein the fifth lens group is a lens group which is positioned closest to the second object,  
       wherein each lens is made of a material having an Abbe number V=(N(x)-1)/N(x-Δδ))-N(x+δλ), wherein N(x) is a refractive index of the material at a wavelength x, and Δλis a wavelength difference, and wherein the material is selected from at least two material groups, namely a first material group whose materials have Abbe numbers (V1) which are higher than a limit value (Vg), and a second material group whose materials have Abbe numbers (V2) which are lower than the limit value (Vg), wherein at least one of the lenses is made of a material of the first material group and has a positive refractive power and at least one of the lenses is made of a material of the second material group and has a negative refractive power,  
       wherein the fifth lens group comprises a partial group of at least three directly successively arranged lenses, wherein the partial group comprises a terminal lens which, of all lenses of the system, is the one which is disposed closest to the second object, and wherein a lens directly adjacent to the partial group is made of a material of the second material group, and wherein all lenses of the partial group are made of materials which are included in the first material group.  
     
     
       2. The projection exposure system according to  claim 1 , wherein the partial group comprises four lenses. 
     
     
       3. The projection exposure system according to  claim 1 , wherein the partial group comprises five lenses. 
     
     
       4. The projection exposure system according to  claim 1 , wherein the partial group comprises at least six lenses. 
     
     
       5. The projection exposure system according to  claim 1 , wherein a lens volume of all lenses made of materials of the second material group is smaller than 20%, preferably, smaller than 15% of a lens volume of all lenses made of materials of the first material group. 
     
     
       6. The projection exposure system according to  claim 1 , wherein the lens made of the material of the second material group and positioned directly adjacent to the partial group has a free diameter D for which it applies: D>0.7 * D max , preferably, D>0.8 * D max  and, more preferred, D>0.9 * D max , wherein D max  is a free diameter of a lens having the largest free diameter of all lenses. 
     
     
       7. The projection exposure system according to  claim 1 , wherein all lenses of the fifth lens group made of materials of the second material group are positioned along the optical axis in a region wherein a first bundle cross-section of a beam bundle emanating from a first outermost field point of the first object is displaced transversely to the optical axis in respect to a second bundle cross-section of a beam bundle emanating from a second outermost field point of the first object positioned diametrically opposed to the first outermost field point by an amount q, so that it applies: q/d<0.1, wherein d is a free diameter of the respective lens. 
     
     
       8. The projection exposure system according to  claim 5 , wherein all lenses of the fifth lens group which are made of materials of the second material group and disposed between a system diaphragm and the second object are disposed in a region along the optical axis wherein q/d ±0.05. 
     
     
       9. The projection exposure system according to  claim 1 , wherein at least one lens of the partial group has a maximum thickness along the optical axis and a free diameter such that a ratio of maximum thickness divided by diameter is larger than 0.3. 
     
     
       10. The projection exposure system according to  claim 1 , wherein the materials of the first material group have a refractive index which is in a range of from 0.93 * NFK5(λ) to 1.03 * NFK5(λ), wherein NFK5(λ) is a refractive index of a FK5 glass of Schott at the working wavelength. 
     
     
       11. The projection exposure system according to  claim 1 , wherein the materials of the first material group have a refractive index at a wavelength of 365.5 nm which is smaller than 1.55. 
     
     
       12. The projection exposure system according to  claim 1 , wherein the materials of the second material group have a refractive index which is in a range of from 0.97 * NLLF1(λ) to 1.07 * NLLF1(λ), wherein NLLF1(λ) is a refractive index of a LLF1 glass of Schott at the working wavelength. 
     
     
       13. The projection exposure system according to  claim 1 , wherein the materials of the second material group have a refractive index at a wavelength of 365.5 nm which is higher than 1.54. 
     
     
       14. The projection exposure system according to  claim 1 , wherein the materials of the second material group have a refractive index which is smaller than 0.99 NLF5(λ), wherein NLF5(λ) is a refractive index of a LF5 glass of Schott at the working wavelength. 
     
     
       15. The projection exposure system according to  claim 1 , wherein the materials of the second material group have a refractive index at a wavelength of 365.5 nm which is smaller than 1.64. 
     
     
       16. The projection exposure system according to  claim 1 , wherein the limit value Vg is determined by the equation 
       
         
             Vg =( VFK 5(λ)+ VLF 5(λ))/2  
         
       
       wherein VFK5(λ) is an Abbe number of a FK5 glass of Schott at the working wavelength and VLF5(λ) is an Abbe number of a LF5 glass of Schott at the working wavelength. 
     
     
       17. The projection exposure system according to  claim 1 , wherein the limit value Vg is 400 if the Abbe number is determined at a wavelength λ=365.5 nm and a wavelength difference Δλ=3 nm. 
     
     
       18. The projection exposure system according to  claim 1 , wherein the first material group comprises quartz glass. 
     
     
       19. The projection exposure system according to  claim 1 , wherein a numerical aperture on the side of the second object is higher than 0.6. 
     
     
       20. The projection exposure system according to  claim 1 , wherein a numerical aperture on the side of the second object is higher than 0.65. 
     
     
       21. The projection exposure system according to  claim 19 , wherein a Strehl number of the system is higher than 0,95, when determined with a light spectrum of a half-width value of 2 nm on both sides of the working wavelength. 
     
     
       22. The projection exposure system according to  claim 1 , wherein a minimum distance between opposed surfaces of each pair of directly adjacent lenses is smaller than 25 mm. 
     
     
       23. The projection exposure system according to  claim 1 , wherein a minimum distance, averaged over all pairs of directly adjacent lenses, between opposed surfaces of the respective pair is smaller than 3 mm. 
     
     
       24. The projection exposure system according to  claim 1 , wherein the projection exposure system is telecentric on both sides thereof. 
     
     
       25. The projection exposure system according to  claim 1 , further comprising a diaphragm which is disposed in a region of the fifth lens group. 
     
     
       26. The projection exposure system according to  claim 1 , wherein the light comprises a light of a mercury-I line. 
     
     
       27. A projection exposure system positionable between a first object and a second object for imaging the first object in a region of the second object with light of a wavelength band having a width δλabout a central working wavelength λ, wherein a relative width δλ/λof the wavelength band is larger than 0.002, comprising: 
       at least a first, second, third, fourth and fifth lens group which are successively positioned in this order between the first and the second object along an optical axis and each of which comprises a plurality of lenses, wherein the first third and fifth lens group each has a positive refractive power and the second and fourth lens group each has a negative refractive power, and wherein the fifth lens group is a lens group which is positioned closest to the second object,  
       wherein each lens is made of a material having an Abbe number V=(N(x)-1)/N(x-Δλ))-N(x+Δλ), wherein N(x) is a refractive index of the material at a wavelength x, and Δλis a wavelength difference, and wherein the material is selected from at least two material groups, namely a first material group whose materials have Abbe numbers (V1) which are higher than a lint value (Vg), and a second material group whose materials have Abbe numbers (V2) which are lower than the limit value (Vg), wherein at least one of the lenses is made of a material of the first material group and has a positive refractive power and at least one of the lenses is made of a material of the second material group and has a negative refractive power,  
       wherein lenses of the fourth lens group are made of materials which are included in the second material group and whose refractive index at a wavelength of 365.5 nm is smaller than 1.59.  
     
     
       28. A projection exposure system positionable between a first object and a second object for imaging the first object in a region of the second object with light of a wavelength band having a width δλabout a central working wavelength λ, wherein a relative width δλ/λof the wavelength band is larger than 0.002, comprising: 
       at least a first, second, third, fourth and fifth lens group which are successively positioned in this order between the first and the second object along an optical axis and each of which comprises a plurality of lenses, wherein the first, third and fifth lens group each has a positive refractive power and the second and fourth lens group each has a negative refractive power, and wherein the fifth lens group is a lens group which is positioned closest to the second object, wherein each lens is made of a material having an Abbe number V=(N(x)-1)/N(x-Δλ))-N(xΔλ), wherein N(x) is a refractive index of the material at a wavelength x, and Δλis a wavelength difference, and wherein the material is selected from at least two material groups, namely a first material group whose materials have Abbe numbers (V1) which are higher than a limit value (Vg), and a second material group whose materials have Abbe numbers (V2) which are lower than the limit value (Vg), wherein at least one of the lenses is made of a material of the first material group and has a positive refractive power and at least one of the lenses is made of a material of the second material group and has a negative refractive power,  
       wherein all lenses of at least one of the first, second, third and fourth lens group are made of materials which are contained in the first material group, and wherein at least one lens of at least one of the first, second, third and fourth lens group comprises at least one aspherical surface.  
     
     
       29. The projection exposure system according to  claim 28 , wherein each lens group comprises at most one lens with aspherical surface. 
     
     
       30. The projection exposure system according to  claim 28 , wherein the at least one lens having the aspherical surface is a lens which, in the direction of the optical axis, is at least one of an outer marginal lens of the lens group, and a lens directly adjacent to the marginal lens. 
     
     
       31. The projection exposure system according to  claim 30 , wherein the lens having the aspherical surface is the outer marginal lens of the lens group and wherein a surface thereof oriented away from the lens group is the aspherical surface. 
     
     
       32. The projection exposure system according to  claim 28 , wherein all lenses of the first and the second and the third lens group are made of materials which are included in the first material group. 
     
     
       33. The projection exposure system according to  claim 32 , wherein furthermore all lenses of the fourth lens group are made of materials which are included in the first material group. 
     
     
       34. The projection exposure system according to  claim 28 , wherein, of the lenses of the first, second and third lens group, the lenses which are made of materials of the second material group account for a lens volume of less than 10% in regard to a lens volume of all lenses made of materials of the second material group. 
     
     
       35. A projection exposure system positionable between a first object and a second object for imaging the first object in a region of the second object with light of a wavelength band having a width δλabout a central working wavelength λ, wherein a relative width δλ/λof the wavelength band is larger than 0.002, comprising: 
       at least a first, second, third, fourth and fifth lens group which are successively positioned in this order between the first and the second object along an optical axis and each of which comprises a plurality of lenses, wherein the first, third and fifth lens group each has a positive refractive power and the second and fourth lens group each has a negative refractive power, and wherein the fifth lens group is a lens group which is positioned closest to the second object,  
       wherein each lens is made of a material having an Abbe number V=(N(x)1)/N(xΔλ))-N(xΔλ), wherein N(x) is a refractive index of the material at a wavelength x, and Δλis a wavelength difference, and wherein the material is selected from at least two material groups, namely a first material group whose materials have Abbe numbers (V1) which are higher than a limit value (Vg), and a second material group whose materials have Abbe numbers (V2) which are lower than the limit value (Vg), wherein at least one of the lenses is made of a material of the first material group and has a positive refractive power and at least one of the lenses is made of a material of the second material group and has a negative refractive power,  
       wherein the lens group disposed closest to the second object comprises at least one pseudo-cemented lens pair, wherein the pseudo-cemented lens pair is formed of a pair of directly adjacent lenses whose lens surfaces which are oriented towards each other are spaced apart from each other at all points in the direction of the optical axis by a distance A which is smaller than 2.5 percent of a free diameter of a larger one of the two lenses, and wherein a first lens of the lens pair is made of a material of the first material group and has a positive refractive power and a second lens of the lens pair is a lens made of a material of the second material group and has a negative refractive power.  
     
     
       36. The projection exposure system according to  claim 35 , wherein the distance A is smaller than 1.25 percent of the free diameter of the larger one of the two lenses. 
     
     
       37. The projection exposure system according to  claim 35 , wherein two pseudo-cemented lens pairs are disposed between a diaphragm and the second object. 
     
     
       38. The projection exposure system according to  claim 35 , wherein the lens surfaces oriented towards each other of the pseudo-cemented lens pair positioned between the diaphragm and the second object are each bulged towards the first object. 
     
     
       39. The projection exposure system according to  claim 35 , wherein the lens surfaces oriented towards each other of the pseudo-cemented lens pair positioned between a diaphragm and the first object are each bulged towards the second object.